The present invention relates to a shell, particularly for sports shoes such as ice skates, roller skates, or trekking boots.
Conventional sports shoes, such as ice skates or roller skates, usually comprise a shell made of plastics, inside which an innerboot, made of soft material for the user's comfort, is to be internally associated.
An inconvenience of these conventional shoes is that the shell is open at the metatarsal region and at the foot instep region and therefore requires two or more fastening devices, constituted by levers, which allow to move the flaps of the shell closer to each other and then fasten them so as to secure the innerboot that can be positioned in the shell and consequently secure the foot that is accommodated in the innerboot.
Accordingly, the use of two or more levers causes an increase in the manufacturing costs of the shoe and increases the overall weight of the shoe. Furthermore the user has to perform several operations in order to fasten the shell or remove the foot from the innerboot.
U.S. Pat. No. 5,171,033 discloses an in-line skate having a shell in which multiple ventilation openings are formed. The edges of said openings are mutually connected by two levers which are arranged transversely to the foot instep regions.
European patent no. 0 551 704 discloses an in-line skate having a removable shoe in which, as a partial solution to the above mentioned drawbacks, the shell is substantially open at the foot instep and metatarsal regions and is provided, only at the toe region, with an element that partially and externally surrounds an innerboot along a direction that is oblique with respect to the longitudinal axis of the wheel supporting frame.
A cuff is articulated to said shell and has a single lever for fastening its flaps at the tibial region.
However, even this solution has drawbacks: the coupling between the innerboot and the shell is not optimum, because the considerable forces transmitted by the foot to the wheel supporting frame can lead to an unintentional disengagement of the innerboot with respect to the shell at the toe region, thus making sports practice dangerous.
Another known in-line skate has a shell formed by two parts: one part is associated with the wheel supporting frame and constitutes a supporting base for the sole and for part of the lateral regions of an innerboot, and the second part, constituted by a tongue, is pivoted transversely at the tip region of the first element, which affects the entire upper part of the foot and part of the tibia.
Said tongue interacts, in the tibial region, with an adapted lever that surrounds, to the rear, a cuff that is articulated to the first part approximately in the malleolar region.
However, even this solution has drawbacks, because it requires the use of a retention element in the foot instep region; said element is constituted by a detachable fastening band constituted for example by material known by the trade-name "Velcro".
In any case, optimum securing of the innerboot is not achieved, and accordingly the transmission of forces from the foot to the wheels is not optimum. This is due, in particular, to the fact that the tongue, made of substantially rigid material, is in contact with the innerboot only in the foot instep region, where it is pressed by the fastening band, and that gaps form, however, between the innerboot and said tongue towards the toe region and therefore allow the innerboot to move with respect to the shell during skating: this relative motion produces ineffective transmission of forces, leading to difficulty in controlling the skate.